Display device and wiring structure

ABSTRACT

According to one embodiment, a display device includes a first substrate including a semiconductor layer, a first inorganic insulating film provided above the semiconductor layer and including a first opening, an organic insulating film provided above the semiconductor layer and including a second opening in a region which overlaps the first opening, a metal film stacked on the semiconductor layer and a pixel electrode provided in the first opening and the second opening to be in contact with the metal film and the semiconductor layer, and the metal film is spaced from a first side surface of the first opening and a second side surface of the second opening.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2016-211427, filed Oct. 28, 2016, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a display device and awiring substrate.

BACKGROUND

Active-matrix type display devices comprising a plurality of pixelsinclude a wiring substrate on which switching elements for driving thepixels are formed. The switching elements are each formed from, forexample, a thin film transistor. Such a display device, in some cases,comprises a contact hole formed therein to connect an electrode of aswitching element to another conductive material formed in a differentlayer on the wiring substrate.

On the other hand, in the same layer where the electrode of theswitching element is formed, it is necessary to provide a space (margin)between the electrode of the switching element and other conductivematerials in order to avoid the electrode of the switching element fromcontacting the other conductive materials.

In recent years, as the definition of display devices is increased, thewidth of the pixels tends to decrease. Therefore, the ratio between thewidth of the electrode and the margin in a pixel is becomingunneglectable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view schematically showing a display device of a firstembodiment.

FIG. 2 is a plan view schematically showing a display area of thedisplay device shown in FIG. 1.

FIG. 3 is an enlarged plan view showing the display area of the displaydevice shown in FIG. 2.

FIG. 4 is a plan view showing another example of the display area of thedisplay device shown in FIG. 2.

FIG. 5 is a cross-sectional view taken along line V-V′ in FIG. 3.

FIG. 6 is a cross-sectional view taken along line VI-VI' in FIG. 3.

FIG. 7 is a plan view schematically showing a display area of a displaydevice according to a second embodiment.

FIG. 8 is a cross-sectional view taken along line VIII-VIII′ in FIG. 7.

FIG. 9 is a plan view schematically showing a display area of a displaydevice according to a third embodiment.

FIG. 10 is a cross-sectional view taken along line X-X′ in FIG. 9.

FIG. 11 is a plan view schematically showing a display area of a displaydevice according to a fourth embodiment.

FIG. 12 is a cross-sectional view taken along line XII-XII′ in FIG. 11.

FIG. 13 is a plan view schematically showing a display area of a displaydevice according to a fifth embodiment.

DETAILED DESCRIPTION

In general, according to one embodiment, a display device comprises: afirst substrate comprising: a semiconductor layer; a first inorganicinsulating film provided above the semiconductor layer and comprising afirst opening in a region which overlaps the semiconductor layer; anorganic insulating film provided above the semiconductor layer andcomprising a second opening in a region which overlaps the firstopening; a metal film stacked on the semiconductor layer on an innerside of the region where the second opening is formed; and a pixelelectrode provided in the first opening and the second opening to be incontact with the metal film and the semiconductor layer, the metal filmbeing spaced from a first side surface of the first opening and a secondside surface of the second opening.

According to another embodiment, a wiring substrate comprises: asemiconductor layer; a first inorganic insulating film provided abovethe semiconductor layer and comprising a first opening in a region whichoverlaps the semiconductor layer; an organic insulating film providedabove the semiconductor layer and comprising a second opening in aregion which overlaps the first opening; a first conductive layerstacked on the semiconductor layer on an inner side of the region wherethe second opening is formed; and a second conductive layer formed inthe first opening and the second opening to be in contact with the firstconductive layer and the semiconductor layer, the first conductive layerbeing spaced from a first side surface of the first opening and a secondside surface of the second opening, and the second conductive layerbeing in contact with the semiconductor layer between the first sidesurface and the first conductive layer.

According to still another embodiment, a display device comprises: asource line, a semiconductor layer electrically connected to the sourceline, a relay electrode electrically connected to the semiconductorlayer and a pixel electrode connected to the relay electrode, a width ofthe relay electrode is less than a width of the source line.

Embodiments will be described hereinafter with reference to theaccompanying drawings. Incidentally, the disclosure is merely anexample, and proper changes within the spirit of the invention, whichare easily conceivable by a skilled person, are included in the scope ofthe invention as a matter of course. In addition, in some cases, inorder to make the description clearer, the widths, thicknesses, shapes,etc., of the respective parts are schematically illustrated in thedrawings, compared to the actual modes. However, the schematicillustration is merely an example, and adds no restrictions to theinterpretation of the invention. Besides, in the specification anddrawings, the structural elements having functions, which are identicalor similar to the functions of the structural elements described inconnection with preceding drawings, are denoted by like referencenumerals, and an overlapping detailed description is omitted unlessotherwise necessary.

First Embodiment

The major configuration explained in the present embodiments can also beapplied to other types of display devices, for example, a liquid crystaldisplay device comprising a liquid crystal layer, a self-light-emittingdisplay device such as an organic electroluminescent (EL) displaydevice, an electronic paper display device comprising an electrophoreticelement and the like.

FIG. 1 is a plan view schematically showing a display device 1 accordingto the first embodiment.

A first direction X and a second direction Y illustrated in the figureare orthogonal to each other but may intersect at an angle other than 90degrees. For example, the first direction X is parallel to short edgesof the display device 1, and the second direction Y is parallel to longedges of the display device 1. The third direction Z is orthogonal toboth the first direction X and the second direction Y and corresponds toa thickness direction of the display device 1. In the followingexplanation, the third direction Z is referred to as upward (or merelyabove), and a direction opposite to the third direction Z is referred toas downward (or merely below). Viewing from an opposite direction to thethird direction Z is referred to as plan view. Further, such expressionsas “the second member above the first member” and “the second memberbelow the first member”, the second member may be in contact with thefirst member or may be separated from the first member. In the case ofthe latter, the third member may be interposed between the first memberand the second member. On the other hand, such expression as “the secondmember on the first member” and “the second member under the firstcomponent”, the second member is in contact with the first member.

The display device 1 comprises a display panel 2, and a driver IC chip3.

The display panel 2 is an active-matrix liquid crystal display panel.The display panel 2 comprises a first substrate SUB1 and a secondsubstrate SUB2 provided above the first substrate SUB1. The firstsubstrate SUB1 and the second substrate SUB2 attach together whileopposing each other along the third direction Z while interposing aliquid crystal layer LC therebetween.

The display panel 2 may be a transmissive type comprising a transmissivedisplay function which selectively passes light from below (an oppositeside to the front surface) to display images, or a reflective typecomprising a reflective display function which selectively reflectslight from above (the front surface side) to display images, or atrans-reflective type comprising both the transmissive display functionand the reflective display function.

The display panel 2 comprises a display area DA and a non-display areaNDA. The display area DA corresponds substantially to a region where theliquid crystal layer LC is provided, and comprises a plurality of pixelsPX arranged, for example, in a matrix along the first direction X andthe second direction Y. The non-display area NDA surrounds the displayarea DA. The driver IC chip 3 for controlling the pixels PX is providedin the non-display area NDA. Although the illustration is omitted, thenon-display area NDA may comprise a driver for controlling the operationof the pixels PX.

An illustration encircled by the solid line provided in the left-handside of FIG. 1 schematically shows an example of an equivalent circuitof a pixel PX. The pixels PX are located respectively in regions eachincluding a switching element SW located at positions where gate lines(scanning lines) G and source lines (signal lines) S cross each other.In the example illustrated, the gate lines G extend along the firstdirection X and the source lines S extend along the second direction Y.Each pixel PX comprises a switching element SW, a pixel electrode PE, acommon electrode CE, a liquid crystal layer LC and the like. Theswitching element SW is formed from, for example, a thin film transistor(TFT). The gate electrode GE of the switching element SW is connected tothe gate line G, the source electrode SE is connected to the source lineS, and the drain electrode DE is connected to the pixel electrode PE.The pixel electrode PE opposes the common electrode CE and drives theliquid crystal layer LC with an electric field produced between thepixel electrode PE and the common electrode CE. The common electrode CEis formed over a plurality of pixels PX.

FIG. 2 is a plan view schematically showing a configuration example ofthe first substrate SUB1 in the display area DA shown in FIG. 1. FIG. 2shows a plane parallel to an X-Y plane defined by the first direction Xand the second direction Y. Only the main structure is shown in thedrawing.

The first substrate SUB1 comprises the gate lines G (G1, G2, . . . ),the source lines S (S1, S2, S3, . . . ), switching elements SW (SW1,SW2, SW3, . . . ), pixel electrodes PE (PE1, PE2, PE3, . . . ) and thelike. The gate lines G each extend along the first direction X and arearranged along the second direction Y with a gap between each adjacentpair thereof. The source lines S each extend along the second directionY and are arranged along the first direction X with a gap between eachadjacent pair thereof. In the example illustrated, the gate lines G andthe source lines S extend straight but they may be bent. In thefollowing explanation, a structure of a pixel PX1 including a switchingelement SW1 located near the intersection between the gate line G1 andthe source line S1, and a pixel electrode PE1 connected to the switchingelement SW1 will be described as a typical example. Note that thestructure of each of the other pixels PX2, PX3, . . . , is similar tothat of the pixel PX1.

In this embodiment, the switching element SW1 is a double-gated thinfilm transistor including a first gate electrode WG11 and a second gateelectrode WG12. A semiconductor layer SC1, which constitutes theswitching element SW1, comprises two regions which cross the gate lineG1. More specifically, the semiconductor layer SC1 is formed intosubstantially a U shape and comprises a first portion SC11 and a secondportion SC12 each extending along the second direction Y to cross thegate line G1, and a third portion SC13 extending along the firstdirection X to connect the first portion SC11 and the second portionSC12 to each other.

The first portion SC11 extends along the second direction Y under thesource line S1 and crosses the gate line G1. The first gate electrodeWG11 corresponds to a region which crosses the first portion SC11 of thegate lines G1. In an end side of the first portion SC11 located betweenthe gate line G1 and the gate line G2, a contact hole CH0 is formed. Thefirst portion SC11 is electrically connected to the source line S1 via aconductive material provided in the contact hole CH0.

The second portion SC12 extends along the second direction Y between thesource lines S1 and S2, and crosses the gate line G1. The second gateelectrode WG12 corresponds to a region which crosses the second portionSC12 of the gate lines G1. Contact holes CH1 and CH2 are formed in anend side of the second portion SC12. The contact hole CH1 is located onan inner side of the region where the contact hole CH2 is formed. In theexample illustrated, the contact hole CH1 is located between the twoadjacent source lines S1 and S2 and between the two adjacent gate linesG1 and G2, and also closer to the gate line G1 than the contact hole CH0formed in the first portion SC11. One end portion of the contact holeCH2 along the second direction Y overlaps the gate line G1. Note thatthe arrangement of the contact holes CH1 and CH2 is not limited to thatof the above-described example, but may be changed as needed. The secondportion SC12 is electrically connected to the pixel electrode PE1 via aconductive material provided on an inner side of the region where thecontact hole CH1 is formed.

The third portion SC13 is provided along the first direction X toconnect the other end side of the first portion SC11 and the other endside of the second portion SC12. That is, the third portion SC13 islocated on an opposite side to the gate line G2 with respect to the gateline G1. In the example illustrated, the third portion SC13 extendsstraight, but may be bent.

The pixel electrode PE1 is provided between the source lines S1 and S2and between the gate lines G1 and G2, and one end portion thereof alongthe second direction Y overlaps the gate line G1. The pixel electrodePE1 includes a contact portion PA1, electrode portions PB1 and aconnection portion PC1. The contact portion PA1 is located near the gateline G1, and one end side thereof along the second direction Y overlapsthe gate line G1. In the region of the contact portion PA1, the contactholes CH1 and CH2 are formed. The electrode portions PB1 extend towardthe gate line G2 from the contact portion PA1. In the exampleillustrated, the pixel electrode PE1 comprises the two electrodeportions PB1, but the number of the electrode portions PB1 may be one tobe sufficient, or may three or more. The connection portion PC1 connectsa plurality of electrode portions PB1 by their ends on a gate line G2side. With this structure, if any of the electrode portions PB1partially are thinned along the first direction X or broken, potentialcan still be supplied to the electrode portions PB1 via the connectionportion PC1. Note that the connection portion PC1 may be omitted.

In the example shown in FIG. 2, the switching element SW1 is adouble-gate thin film transistor, but not limited to this. For example,a single-gate thin film transistor may be employed as well.

FIG. 3 shows an expanded view of the vicinity of the contact holes CH1and CH2 shown in FIG. 2. Here, the illustration of the pixel electrodesPE is omitted. The contact hole CH3 is formed on an inner side of theregion where the contact hole CH1 is formed. Within the region where thecontact hole CH2 is formed, the relay electrode RE which overlaps atleast the contact hole CH3 is formed. The semiconductor layer SC1 iselectrically connected to the pixel electrode PE (not shown) provided inthe contact holes CH2, CH1 and CH3 via the relay electrode RE.

The contact hole CH2 substantially overlaps the second portion SC12 ofthe semiconductor layer SC1. The contact hole CH2 is illustrated tohave, for example, a rectangular shape comprising edges CH2 a and CH2 bopposing the first direction X and edges CH2 c and CH2 d opposing thesecond direction Y.

A distance between the edges CH2 a and CH2 b of the contact hole CH2along the first direction X, i.e., a width H2 of the contact hole CH2along the first direction X is less an interval H0 between the sourcelines S1 and S2 along the first direction X. In the example illustrated,the contact hole CH2 is located in substantially a central portionbetween the source lines S1 and S2. In other words, a distance betweenthe edge CH2 a and the source line S1 along the first direction X and adistance between the edge CH2 b and the source line S2 along the firstdirection X are substantially the same, which is E1. Note that thecontact hole CH2 may be formed to be close to one of the source lines S1and S2. The contact hole CH2 as such is formed in a fourth insulatingfilm (organic insulating film), which will be described later. Thecontact hole CH1 is formed in a region on an inner side of the contacthole CH2. Therefore, the contact hole CH1 overlaps the second portionSC12 of the semiconductor layer SC1 and the contact hole CH2. Thecontact hole CH1 has, for example, a rectangular shape comprising edgesCH1 a and CH1 b opposing the first direction X and edges CH1 c and CH1 dopposing the second direction Y.

A distance between the edges CH1 a and CH1 b of the contact hole CH1along the first direction X, i.e., a width H1 of the contact hole CH1along the first direction X is less than the width H2 of the contacthole CH2 along the first direction X. In the example illustrated, thecontact hole CH1 is located in substantially a central portion of thecontact hole CH2. In other words, the edges CH1 a, CH1 b, CH1 c and CH1d of the contact hole CH1 are located on an inner side as compared tothe edges CH2 a, CH2 b, CH2 c and CH2 d of the contact hole CH2,respectively, substantially equally by only a distance E2. Note that thecontact hole CH1 should just be located on an inner side of the contacthole CH2 in plan view and may be formed to be close to any one of theedges CH2 a, CH2 b, CH2 c and CH2 d of the contact hole CH2. The contacthole CH1 as such is formed in a fifth insulating film (capacitivenitride film), which will be discussed later.

The contact hole CH3 is formed in the region on an inner side of thecontact hole CH1. Thus, the contact hole CH3 overlaps the second portionof the semiconductor layer SC1, the contact hole CH2 and the contacthole CH1. The contact hole CH3 is illustrated to have, for example, arectangular shape and is located in substantially a central portion ofthe contact hole CH1. A width H3 of the contact hole CH3 along the firstdirection X of is less than the width H1 of the contact hole CH1 alongthe first direction X. Note that the contact hole CH3 should just belocated inside the contact hole CH1 in plan view and may be formed closeto any one of the edges CH1 a, CH1 b, CH1 c and CH1 d of the contacthole CH1. The contact hole CH3 as such is formed in a second insulatingfilm and a third insulating film (a gate insulating film and aninterlayer insulating film), which will be discussed later, to exposethe second portion SC12 of the semiconductor layer SC1.

The relay electrode RE is located on an inner side of the region wherethe contact hole CH2 is formed. In the example illustrated, the relayelectrode RE comprises regions which overlap the contact hole CH1, CH2and CH3, respectively. The relay electrode RE is illustrated to have,for example, a rectangular shape comprising edges REa and REb opposingthe first direction X and edges REc and REd opposing the seconddirection Y.

A distance between the edges REa and REb of the relay electrode RE alongthe first direction X, i.e., a width HR of the relay electrode RE alongthe first direction X is less than the width H3 of the contact hole CH3along the first direction X. Note that the width HR should just be equalto or less than the width H3. The width HR may be equal to or less than,for example, a width A1 of the source line S along the first directionX. In order to meet the demand for a higher definition, in which thewidth (or interval H0) of the pixels PX need to be reduced, the width HRshould desirably be reduced to less than the width A1. The source linesS need to have a certain dimension in width A1 in consideration of theyield in manufacture to avoid disconnection of wiring, etc., but therelay electrode RE can be formed to be more slender than the sourcelines S since such a disconnection problem need not be taken intoconsideration.

In the example illustrated, the relay electrode RE is located insubstantially a central portion of the contact hole CH2 along the firstdirection X and close to the edge CH2 c of the contact hole CH2 alongthe second direction Y. That is, the edges REa and REb of the relayelectrode RE are located on an inner side along the first direction X ascompared respectively to the edges CH2 a and CH2 b of the contact holeCH2 substantially equally by only the distance E3 and also on an innerside of the contact hole CH3. On the other hand, the edge REc of therelay electrode RE is located between the edge CH2 c of the contact holeCH2 and the edge CH1 c of the contact hole CH1 along the seconddirection Y, and the edge REd is located on an inner side of the contacthole CH3. Note that the relay electrode RE should just be located on theinner side of the contact hole CH2 and comprise a region which overlapsthe contact hole CH3 in plan view, and may be formed close to any one ofthe edge CH2 a, CH2 b and CH2 d of the contact hole CH2.

The distance E3 is set to be greater than the distance E1. Thus, evenif, for example, the position of the contact hole CH2 is displaced alongthe first direction X during the manufacture of the display device 1,the relay electrode RE is formed on the inner side of the region wherethe contact hole CH2 is formed.

In this embodiment, a minimum dimension W of the pixel PX along thefirst direction X is defined as a distance (or a pitch of the sourcelines) along the first direction X between an end portion of the sourceline S1 in the first direction X and an end portion of the source lineS2 in the first direction X. When a width of the source line S1 and thesource line S2 along the first direction X is represented by A1, theminimum dimension W of the pixel PX in the above-described configurationis expressed by:

W−(E1×2)+(E2×2)+H1+A1.

Note that in the above-provided explanation, the contact holes CH1, CH2and CH3 are illustrated to have a rectangular shape in the X-Y plane,but may be formed into some other shape. For example, as shown in FIG.4, when the contact holes CH0, CH1, CH2 and CH3 are circular, the widthsH1, H2 and H3 of the contact holes CH1, CH2, and CH3 along the firstdirection X are equivalent to diameters of the contact holes CH1, CH2and CH3. Further, the edges CH1 a and CH1 b and the edges CH2 a and CH2b are equivalent to two points on each of respective circumferencesopposing the first direction X, whereas the edges CH1 c and CH1 d andthe edges CH3 c and CH3 d are equivalent to two points on each ofrespective circumferences opposing the second direction Y. Note that ifthe contact hole CH1, CH2, and CH3 are not rectangular or circular, butof an elliptical shape or that of a combination of, for example,straight lines and curves, the widths H1, H2 and H3 of the contact holeCH1, CH2 and CH3 along the first direction X are considered to be thegreatest intervals along the first direction X.

FIG. 5 is a cross section taken along line V-V′ shown in FIG. 3. FIG. 5shows a plane parallel to the X-Z plane defined by the first direction Xand the third direction Z.

The display device 1 comprises a first substrate SUB1, a secondsubstrate SUB2 and a liquid crystal layer LC held between the firstsubstrate SUB1 and the second substrate SUB2.

The first substrate SUB1 is formed from a transparent first insulatingsubstrate 10 of a glass or resin substrate, or the like. The firstsubstrate SUB1 comprises, on a side of the first insulating substrate10, which opposes the second substrate SUB2, semiconductor layers SC1and SC2, source lines S1 and S2, a relay electrode RE, a pixel electrodePE1, a common electrode CE, a first alignment film AL1, a firstinsulating film 11, a second insulating film 12, a third insulating film13, a fourth insulating film 14, a fifth insulating film 15, etc.

The first insulating film 11 is formed on the first insulating substrate10 and functions as an undercoat layer of the semiconductor layer SC1.The semiconductor layers SC1 and SC2 are formed on the first insulatingfilm 11. A first portion SC11 and a second portion SC12 of thesemiconductor layer SC1 and a first portion SC21 of the semiconductorlayer SC2 are spaced apart from each other along the first direction X.The second insulating film 12 is a gate insulating film, which coversthe semiconductor layers SC1 and SC2, and is formed also on the firstinsulating film 11. Although not shown in FIG. 5, the gate lines G areformed on the second insulating film 12. The third insulating film 13 isan interlayer insulating film provided on the second insulating film 12and the gate lines G (not shown). The first insulating film 11, thesecond insulating film 12, and the third insulating film 13 are eachformed from, for example, an inorganic insulating material such assilicon oxide, silicon nitride or silicon oxynitride.

In this embodiment, the second insulating film 12 and the thirdinsulating film 13 each may be called “a second inorganic insulatingfilm”. In the second inorganic insulating film (namely, the thirdinsulating film 13 and the second insulating film 12) of the regionwhere the second portion SC12 of the semiconductor layer SC1 isprovided, a contact hole CH3 (third opening) penetrating to the secondportion SC12 of the semiconductor layer SC1 is formed. In other words,the contact hole CH3 overlaps partially the second portion SC12 of thesemiconductor layer SC1.

In the following explanation, side surfaces of the third insulating film13 and the second insulating film 12 which constitute the contact holeCH3 may be called “a side surface of the contact hole CH3”. Further, theboundary between the side surface of the contact hole CH3 and the secondportion SC12 of the semiconductor layer SC1 may be called an “edge” ofthe contact hole CH3. FIG. 5 shows an edge CH3 a as a typical example.That is, the edge CH3 a is equivalent to the boundary between one sidesurface CH3A of the contact hole CH3 along the first direction X and thesecond portion SC12 of the semiconductor layer SC1.

The relay electrode RE (metallic film) is stacked on the second portionSC12 of the semiconductor layer SC1 in the contact hole CH3. In theexample illustrated, the relay electrode RE is spaced from one sidesurface CH3A of the contact hole CH3 along the first direction X andanother side surface CH3B thereof. That is, as shown in FIG. 5, therelay electrode RE is configured not to cover the entire opening regionof the contact hole CH3 but to expose a portion of the second portionSC12 of the semiconductor layer SC1 in the region where the relayelectrode RE is not formed. The relay electrode RE is formed from, forexample, a metal material such as aluminum or titanium. Note that theedge REa of the relay electrode RE shown in FIG. 3 is equivalent to theone end of the relay electrode RE along the first direction X. FIG. 5shows only the edge REa as a typical example, but the other edges REb,REc and Red have a configuration similar to the above.

The source lines S1 and S2 are formed on the third insulating film 13.The source line S2 is located on an opposite side to the source line S1with respect to the contact hole CH1. The source lines S1 and S2 areformed in the same manufacturing process and from the same material asthose of the relay electrode RE.

The fourth insulating film 14 (organic insulating film) covers thesource lines S1 and S2 and is formed also on the third insulating film13. The fourth insulating film 14 is a planarizing film formed from, forexample, an organic insulating material such as polyimide.

The fourth insulating film 14 comprises the contact hole CH2 (secondopening) formed therein to penetrate to the third insulating film 13, ina region which further includes the region where the contact hole CH3 isprovided. In other words, the contact hole CH2 includes a regionoverlapping the second portion SC12 of the semiconductor layer SC1, thecontact hole CH3 and the relay electrode RE.

In the following explanation, a side surface of the fourth insulatingfilm 14 which constitutes the contact hole CH2 may be called “a sidesurface of the contact hole CH2”. The edge CH2 a of the contact hole CH2shown in FIG. 3 is equivalent to a boundary between one side surfaceCH2A of the contact hole CH2 along the first direction X and the thirdinsulating film 13. FIG. 5 shows the edge CH2 a as a typical example,and the other edges have a configuration similar to that of the above.

The common electrode CE is formed on the fourth insulating film 14except the region where the contact hole CH2 is formed. The fifthinsulating film 15 covers the common electrode CE and is formed also onthe fourth insulating film 14. The fifth insulating film 15 covers theside surfaces CH2A and CH2B of the contact hole CH2 and also is incontact with the third insulating film 13 in the contact hole CH2. Thefifth insulating film 15 is a capacitive nitride film formed from, forexample, an inorganic insulating material such as silicon nitride orsilicon oxynitride, and forms a capacitance between the common electrodeCE and the pixel electrode PE, which will be described later. In thisembodiment, the fifth insulating film 15 may be called “a firstinorganic insulating film”.

The fifth insulating film 15 comprises a contact hole CH1 (firstopening) formed therein to penetrate to the third insulating film 13 ina region on an inner side of the region where the contact hole CH2 isformed, and also including the region where the contact hole CH3 isformed. In other words, the contact hole CH1 includes a regionoverlapping the second portion SC12 of the semiconductor layer SC1, thecontact hole CH3, the relay electrode RE and the contact hole CH2.

In the following explanation, a side surface of the fifth insulatingfilm 15 which constitutes the contact hole CH1 may be called “a sidesurface of the contact hole CH1”. The edge CH1 a of the contact hole CH1shown in FIG. 3 is equivalent to a boundary between the one side surfaceCH1A of the contact hole CH1 along the first direction X and the thirdinsulating film 13. FIG. 5 shows the edge CH1 a as a typical example,and the other edges have a configuration similar to that of the above.

Note that the relay electrode RE is spaced apart also from the sidesurfaces CH2A and CH2B of the contact hole CH2 and the side surfacesCH1A and CH1B of the contact hole CH1.

The pixel electrode PE is provided in the contact holes CH1, CH2 and CH3and to be in contact with at least the relay electrode RE. Thus, thepixel electrode PE and the semiconductor layer SC1 are electricallyconnected to each other via the relay electrode RE.

Specifically, in the contact hole CH2, the pixel electrode PE covers thefifth insulating film 15. In the contact hole CH1, the pixel electrodePE covers the side surfaces CH1A and CH1B of the contact hole CH1 alongthe first direction X and also is in contact with the third insulatingfilm 13 exposed by the contact hole CH1. In the contact hole CH3, thepixel electrode PE covers the side surfaces CH3A and CH3B of the contacthole CH3 along the first direction X and also is in contact with therelay electrode RE. In the example illustrated, the pixel electrode PEis in contact also with the second portion SC12 of the semiconductorlayer SC1 between the side surface CH3A and the relay electrode RE andbetween the side surface CH3B and the relay electrode RE. In otherwords, in the contact hole CH3, the relay electrode RE and the pixelelectrode PE are in contact with the second portion SC12 of thesemiconductor layer SC1.

The common electrode CE and the pixel electrode PE are each formed from,for example, a transparent conductive material such as indium tin oxide(ITO) or indium zinc oxide (IZO).

The pixel electrode PE and the fifth insulating film 15 are covered bythe first alignment film AL1.

On the other hand, the second substrate SUB2 is formed from atransparent second insulating substrate 20 of a glass or resin substrateor the like. The second substrate SUB2 comprises, on a side of thesecond insulating substrate 20, which opposes the first substrate SUB1,a light-shielding film BM, a color filter layer 21, an overcoat layerOC, a second alignment film AL2, etc. The light-shielding film BM isformed on a side of the second insulating substrate 20, which opposesthe first substrate SUB1, so as to partition the pixels PX from eachother. The color filter layer 21 is formed on a side of the secondinsulating substrate 20, which opposes in first substrate SUB1. Thecolor filter layer 21 includes a plurality of color filters, which arenot illustrated. The color filter is formed from, for example, a resinmaterial colored in red, green, blue or the like. The overcoat layer OCis formed from a transparent resin material, so as to cover the colorfilter layer 21. The overcoat layer OC is covered by the secondalignment film AL2. Note that the color filter layer 21 may be providedin the first substrate SUB1.

The first substrate SUB1 and the second substrate SUB2 configured asabove are disposed to oppose each other so that the first alignment filmAL1 and the second alignment film AL2 are arranged to oppose each other,and then they are attached together with a sealing material, which isnot illustrated. Between the first alignment film AL1 and the secondalignment film AL2, a liquid crystal composition containing liquidcrystal molecules is sealed and thus the liquid crystal layer LC isformed.

FIG. 6 is a cross section taken along line VI-VI′ shown in FIG. 3. FIG.6 shows a plane parallel to the Y-Z plane defined by the seconddirection Y and the third direction Z. Here, only the first substrateSUB1 is shown and the illustration of the liquid crystal layer LC andthe second substrate SUB2 is omitted.

The structure from the first insulating substrate 10 to the secondinsulating film 12 is the same as that shown in FIG. 5, and thereforethe explanation thereof is omitted.

The gate line G1 is formed on the second insulating film 12. The gateline G1 overlaps the second portion SC12 of the semiconductor layer SC1.The third insulating film 13 covers the gate line G1 and also is formedon the second insulating film 12.

The contact hole CH3 and the contact hole CH1 are spaced apart from thegate line G1 along the second direction Y. On the other hand, thecontact hole CH2 partially overlaps the gate line G1.

The relay electrode RE is formed on the second portion SC12 of thesemiconductor layer SC1 in the contact hole CH3 and also one end portionthereof along the second direction Y is in contact with one side surfaceCH3C of the contact hole CH3 along the second direction Y. On the otherhand, the other end portion of the relay electrode RE along the seconddirection Y is spaced apart from another side surface CH3D of thecontact hole CH3 along the second direction Y. In the exampleillustrated, the relay electrode RE covers the side surface CH3C of thecontact hole CH3 and also formed on the third insulating film 13 in thecontact holes CH1 and CH2. In other words, the relay electrode RE is incontact with the third insulating film 13 in the contact holes CH1 andCH2. The relay electrode RE formed on the third insulating film 13 isspaced from the side surface CH2C of the contact hole CH2 along thesecond direction Y and is partially covered by the fifth insulating film15.

The fifth insulating film 15 covers the side surfaces CH2C and CH2D ofthe contact hole CH2 and also is in contact with the third insulatingfilm 13 in the contact hole CH2. Further, the fifth insulating film 15covers one end portion of the relay electrode RE formed on the thirdinsulating film 13 in the contact hole CH2. In other words, the fifthinsulating film 15 is in contact with the relay electrode RE in thecontact hole CH2 and also with the third insulating film 13 between theone end portion of the relay electrode RE along the second direction Yand the side surface CH2C of the contact hole CH2.

The pixel electrode PE is in contact with the relay electrode RE in thecontact hole CH3 and also with the second portion SC12 of thesemiconductor layer SC1 between the side surface CH3D of the seconddirection Y and the relay electrode RE. The pixel electrode PE coversone side surface CHIC along the second direction Y and also is incontact with the relay electrode RE in the contact hole CH1. Further,the pixel electrode PE covers another side surface CH1D along the seconddirection Y and also is in contact with the third insulating film 13 inthe contact hole CH1. The pixel electrode PE covers the fifth insulatingfilm 15 in the contact hole CH2.

Note that the arrangement of the relay electrode RE in the X-Y plane isnot limited to that described above. The arrangement of the relayelectrode RE may be rotated by 90 degrees in the X-Y plane. Further, theshape of the relay electrode RE is not limited to rectangular, but maybe, for example, circular, or elliptical or a shape consisting of astraight line and a curve. The width HR of the relay electrode can bedefined as the width in its bottom portion along the first direction X.

According to this embodiment, the width HR of the relay electrode RE isset equal to or less than the width H3 of the contact hole CH3 along thefirst direction X, and thus the minimum dimension W of the pixel PX canbe reduced. For example, if the width HR of the relay electrode RE isgreater than the width H3 of the contact hole CH3, the both end portionsof the relay electrode RE along first direction X are formed on thethird insulating film 13. In this case, it is required to provide amargin so as to avoid the source lines S and the relay electrode REformed in the same layer from being contact with each other. For thisreason, the minimum dimension W of the pixels PX along the firstdirection X must increase by this margin. By contrast, according to thisembodiment, while the source line S is formed on the third insulatingfilm 13 in the first direction X, the relay electrode RE is formed onthe semiconductor layer SC1 and thus not arranged to be adjacent to thesource lines S on the third insulating film 13. Therefore, it is notnecessary to provide a margin between the source lines S and the relayelectrode RE. Thus, a higher definition of the display device 1 isachieved.

Moreover, according to this embodiment, the fourth insulating film 14comprising the contact hole CH2 formed therein is formed on the thirdinsulating film 13. The side surfaces CH2A, CH2B, CH2C and CH2D of thecontact hole CH2 are covered by the fifth insulating film 15, and thefifth insulating film 15 is in contact with the third insulating film 13in the contact hole CH2. That is, the fourth insulating film 14 formedfrom an organic insulating material is covered with the inorganicinsulating material. Therefore, discharge of gas from the fourthinsulating film 14 of the organic insulating materials to the liquidcrystal layer LC can be suppressed. Further, the fourth insulating film14 and the conductive layers, for example, the pixel electrode PE, inthe contact hole CH1, CH2 and CH3 are shut off from each other by thefifth insulating film 15. Therefore, the entering of moisture from thefourth insulating film 14 to the region where the contact hole CH1, CH2and CH3 are formed can be suppressed, thereby suppressing the corrosionof the conductive layers in the contact hole CH1, CH2 and CH3. Thus, thereliability of the contact portion can be improved.

Second Embodiment

FIG. 7 is a plan view schematically showing a display device 1 accordingto the second embodiment. The second embodiment is different from thefirst embodiment in that both end portions of the relay electrode REalong the second direction Y are located on an inner side of the contacthole CH1. More specifically, an edge REc of the relay electrode RE islocated between an edge CH3 c of the contact hole CH3 and an edge CHicof the contact hole CH1, and the edge REd is located between an edge CH3d of the contact hole H3 and the edge CH1 d of the contact hole CH1.

FIG. 8 shows a cross section taken along line VIII-VIII′ shown in FIG.7. FIG. 8 shows a plane parallel to the Y-Z plane defined by the seconddirection Y and the third direction Z. Here, only the first substrateSUB1 is shown.

The relay electrode RE is formed on the second portion SC12 of thesemiconductor layer SC1 in the contact hole CH3 and also in contact withside surfaces CH3C and CH3D of the contact hole CH3 along the seconddirection Y. In the example illustrated, the relay electrode RE coversthe side surfaces CH3C and CH3D of the contact hole CH3 and is formedalso on the third insulating film 13 in the contact hole CH1. The relayelectrode RE formed on the third insulating film 13 in the contact holeCH1 is spaced from the side surfaces CH1C and CH1D of the contact holeCH1 and the side surfaces CH2C and CH2D of the contact hole CH2.

The pixel electrode PE is in contact with the relay electrode RE in thecontact hole CH3. The pixel electrode PE covers the relay electrode REand the fifth insulating film 15 in the contact hole CH1 and also is incontact with the third insulating film 13. In other words, the pixelelectrode PE is in contact with the third insulating film 13 between theside surface CH1C and the relay electrode RE and between the sidesurface CH1D and the relay electrode RE in the contact hole CH1.

In this embodiment as well, an advantageous effect similar to that ofthe first embodiment can be obtained. Further, since a contact area canbe assured between the relay electrode RE and the second portion SC12 ofthe semiconductor layer SC1, the conductivity between the semiconductorlayer SC1 and the relay electrode RE can be improved.

Third Embodiment

FIG. 9 is a plan view schematically showing a display device 1 accordingto the third embodiment. Third embodiment is different from the firstembodiment in that the relay electrode RE is close to an edge CH3 b ofthe contact hole CH3 along the first direction X. In the exampleillustrated, the edge REb of the relay electrode RE overlaps the edgeCH3 b of the contact hole CH3.

FIG. 10 shows a cross section taken along line X-X′ shown in FIG. 9.FIG. 10 shows a plane parallel to the X-Z plane defined by the firstdirection X and the third direction Z. Here, only the first substrateSUB1 is shown.

One end portion of the relay electrode RE along the first direction X isin contact with the side surface CH3B of the contact hole CH3 in thecontact hole CH3. On the other hand, the other end portion of the relayelectrode RE along the first direction X is spaced from the side surfaceCH3A of the contact hole CH3. The pixel electrode PE is in contact withthe relay electrode RE in the contact hole CH3 and also with the secondportion SC12 of the semiconductor layer SC1 between the relay electrodeRE and the side surface CH1A of the contact hole CH1. In this embodimentas well, an advantageous effect similar to that of the first embodimentcan be obtained.

Fourth Embodiment

FIG. 11 is a plan view schematically showing a display device 1according to the fourth embodiment. The fourth embodiment is differentfrom the first to third embodiments in that the first substrate SUB1does not comprise the contact hole CH1.

FIG. 12 shows a cross section taken along line XII-XII′ shown in FIG.11.

As shown in FIG. 12, in the fourth embodiment, the common electrode CEis provided above the pixel electrode PE. In this embodiment, the secondinsulating film 12 and the third insulating film 13 may be called a“first inorganic insulating film”, and the fifth insulating film 15 maybe called “a second inorganic insulating film”. Further, in thisembodiment, the contact hole CH3 formed in the second insulating film 12and the third insulating film 13 corresponds to the first opening. Thatis, in this embodiment, the first inorganic insulating film (the secondinsulating film 12 and the third insulating film 13) comprises the firstopening (the contact hole CH3) which exposes the semiconductor layer SC1and the relay electrode RE.

The pixel electrode PE is provided between the source line S1 and thesource line S2 on the fourth insulating film 14 (the organic insulatingfilm) and in the contact hole CH2 (the second opening) and the contacthole CH3 (the first opening). The pixel electrode PE covers the sidesurfaces CH2A and CH2B along the first direction X in the contact holeCH2 and also is in contact with the third insulating film 13 exposed bythe contact hole CH2. The pixel electrode

PE covers the side surfaces CH3A and CH3B along the first direction Xand the relay electrode RE in the contact hole CH3 and also is formed onthe second portion SC12 of the semiconductor layer SC1 exposed by thecontact hole CH3. In other words, the pixel electrode PE is in contactwith the second portion SC12 of the semiconductor layer SC1 between theside surface CH3A of the contact hole CH3 and the relay electrode RE andbetween the side surface CH3B of the contact hole CH3 and the relayelectrode RE.

The fifth insulating film 15 (the second inorganic insulating film)covers the pixel electrode PE and also is formed on the fourthinsulating film 14. In this embodiment, the fifth insulating film 15does not comprise an opening. The common electrode CE is provided on thefifth insulating film 15. The common electrode CE is covered by thefirst alignment film AL1.

In this embodiment as well, an advantageous effect similar to that ofthe first embodiment can be obtained. Further, in this embodiment, thepixel electrode PE covers the side surfaces CH2A, CH2B, CH2C and CH2D ofthe contact hole CH2, the third insulating film 13 exposed by thecontact hole CH2 and the side surfaces CH3A, CH3B, CH3C and CH3D of thecontact hole CH3, collectively. The fifth insulating film 15 and thecommon electrode CE are provided also in the contact holes CH2 and CH3so as to cover the pixel electrode PE. Thus, the sealing property of thefourth insulating film 14 in the contact portion can be improved, thusenhancing the reliability of the contact portion.

Fifth Embodiment

FIG. 13 is a cross section schematically showing a display device 1according to the fifth embodiment. The fifth embodiment is differentfrom the fourth embodiment in that the display device is an organic ELdisplay device.

The display device 1 comprises a first substrate SUB1 and a secondsubstrate SUB2.

The first substrate SUB1 is formed from a first insulating substrate 30of, for example, an organic insulating material such as polyimide. Thefirst insulating substrate 30 may have flexibility. The first substrateSUB1 comprises, above the first insulating substrate 30, i.e., on a sidewhich opposes the first substrate SUB2, a switching element SW, anorganic EL device OD as a light-emitting device, a first insulating film11, a second insulating film 12, a third insulating film 13, a fourthinsulating film 14, a sixth insulating film 16, a protective film 50,etc. Further, under the first insulating substrate 30, a protectionmember PP is provided via an adhesive layer (not shown). The protectionmember PP is a protection film which protects the first insulatingsubstrate 30 and is formed of, for example, polyethylene terephthalate(PET).

The first insulating film 11 is formed on the first insulating substrate30. The switching element SW is formed on the first insulating film 11.The switching element SW is formed from, for example, a thin filmtransistor (TFT). The switching element SW comprises a semiconductorlayer SC, a gate electrode GE, a source electrode SE and a drainelectrode DE. The semiconductor layer SC is formed on the firstinsulating film 11, and is covered by the second insulating film 12. Thegate electrode GE is formed on the second insulating film 12, and iscovered by the third insulating film 13. The source electrode SE isformed on the third insulating film 13, and is connected to thesemiconductor layer SC via a contact hole formed in the third insulatingfilm 13 and the second insulating film 12.

In this embodiment, the second insulating film 12 and the thirdinsulating film 13 may be called a “first inorganic insulating film”.Further, in this embodiment, the contact hole CH3 formed in the secondinsulating film 12 and the third insulating film 13 corresponds to thefirst opening. That is, in this embodiment, the first inorganicinsulating film (the second insulating film 12 and the third insulatingfilm 13) comprises the first opening (the contact hole CH3) in a regionwhich overlaps with the semiconductor layer SC1.

The contact hole CH3 (the first opening) is provided in the thirdinsulating film 13 and the second insulating film 12 and on oppositeside to the source electrode SE with respect to the gate electrode GE.The drain electrode DE is formed on the semiconductor layer SC exposedby the contact hole CH3. The drain electrode DE corresponds to the relayelectrode RE in the first embodiment. The drain electrode DE is spacedapart from the side surfaces CH3A and CH3B of the contact hole CH3.

The fourth insulating film 14 (the organic insulating film) covers theswitching element SW and also is formed on the third insulating film 13.The fourth insulating film 14 is formed from, for example, an organicinsulating material such as polyimide. The contact hole CH2 (the secondopening) is formed in a region within the fourth insulating film 14,which overlaps the contact hole CH3. The contact hole CH2 is wider thanthe contact hole CH3.

The organic EL device OD is formed on the fourth insulating film 14. Theorganic EL device OD comprises a pixel electrode PE, an organiclight-emitting layer ORG and a common electrode CE. In the exampleillustrated, the organic EL device OD is a top emission types, whichemit light to an opposite side to the first insulating substrate 30, butnot limited to this example. For example, it may be a bottom emissiontype, which emits light to a first insulating substrate 30 side.Although not shown, in the case where the display device 1 is of a topemission type, the organic EL device OD should desirably comprise areflective layer between the fourth insulating film 14 and the pixelelectrode PE. The reflective layer is formed from, for example, a highlyreflective metal material such as aluminum.

The pixel electrode PE is provided on the fourth insulating film 14 andalso in the contact holes CH2 and CH3, and is in contact with, i.e.,electrically connected to the drain electrode DE. The pixel electrode PEcovers the side surfaces CH2A and CH2B in the contact hole CH2 and alsois formed on the third insulating film 13 exposed by the contact holeCH2. The pixel electrode PE covers the side surface CH3A and CH3B andthe drain electrode DE in the contact hole CH3, and also is formed onthe semiconductor layer SC. In other words, the pixel electrode PE is incontact with the semiconductor layer SC between the side surface CH3A ofthe contact hole CH3 and the drain electrode DE, and between the sidesurface CH3B of the contact hole CH3 and the drain electrode DE.

The organic light-emitting layer ORG emits light at the brightnessaccording to voltage (or current) applied between the pixel electrode PEand the common electrode. The organic light-emitting layer ORG maycomprises additional layers other than a light-emitting layer, such asan electron injection layer, a hole injection layer, an electrontransport layer, a hole transport layer and the like, in order toimprove light-emitting efficiency.

The common electrode CE is formed on the organic light-emitting layerORG. The common electrode CE and the pixel electrode PE are formed from,for example, a transparent conductive material such as indium tin oxide(ITO) or indium zinc oxide (IZO).

The sixth insulating film 16 is formed on the pixel electrode PE so asto partition the organic EL device OD into each and every pixel. Thatis, in the region where the sixth insulating film 16 is formed, thepixel electrode PE and the organic light-emitting layer ORG are notbrought into contact with each other (insulated from each other).Therefore, even if voltage is applied between the pixel electrode PE andthe common electrode CE, the organic light-emitting layer ORG does notemit light. In the example illustrated, each pixel comprises an organiclight-emitting layer which emits blue, an organic light-emitting layerwhich emits green and an organic light-emitting layer which emits red.The organic EL device OD is sealed with the protective film 50, whichprotects the organic EL device OD from moisture and the like.

On the other hand, the second substrate SUB2 is formed from a glass orresin substrate, or an optical element such as an optical film or apolarizer. The second substrate SUB2 is disposed so as to oppose thefirst substrate SUB1. The first substrate SUB1 and the second substrateSUB2 are attached together with an adhesive 41.

In the example illustrated, the pixels comprise organic light-emittinglayers ORG which emit different colors, respectively, but a commonorganic light-emitting layer ORG may be provided over a plurality ofpixels PX. In such a structure, the second substrate SUB2 comprises acolor filter in a region which covers at least the organiclight-emitting layers ORG.

In this embodiment as well, an advantageous effect similar to that ofthe fourth embodiment can be obtained.

In each of the above-provided embodiments, the second portion SC12corresponds to the semiconductor layer. The relay electrode REcorresponds to the metallic film or a first conductive layer. The pixelelectrode PE corresponds to the pixel electrode or the second conductivelayer. The source line S1 corresponds to a first wiring portion and thesource line S2 corresponds to a second wiring portion.

In the first to third embodiments, the fifth insulating film 15corresponds to the first inorganic insulating film. The fourthinsulating film 14 corresponds to the organic insulating film locatedbetween the semiconductor layer and the first inorganic insulating film.The second insulating film 12 and the third insulating film 13correspond to the second inorganic insulating film. The contact hole CH1corresponds to the first opening. The side surface CH1A corresponds tothe first side surface. The side surface CH1C corresponds to the fourthside surface. The contact hole CH2 corresponds to the second opening.The side surface CH2A corresponds to the second side surface. Thecontact hole CH3 corresponds to the third opening. The side surface CH3Acorresponds to the third side surface.

In fourth embodiment, the fourth insulating film 14 corresponds to theorganic insulating film. The second insulating film 12 and the thirdinsulating film 13 correspond to the first inorganic insulating filmlocated between the semiconductor layer and the organic insulating film.The fifth insulating film 15 corresponds to the second inorganicinsulating film. The contact hole CH3 corresponds to the first opening.The side surface CH3A corresponds to the first side surface. The contacthole CH2 corresponds to the second opening. The side surface CH2Acorresponds to the second side surface.

In the fifth embodiment, the fourth insulating film 14 corresponds tothe organic insulating film. The second insulating film 12 and the thirdinsulating film 13 correspond to the first inorganic insulating filmlocated between the semiconductor layer and the organic insulating film.The contact hole CH3 corresponds to the first opening. The side surfaceCH3A corresponds to the first side surface. The contact hole CH2corresponds to the second opening. The side surface CH2A corresponds tothe second side surface.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A display device comprising: a first substratecomprising: a semiconductor layer; a first inorganic insulating filmprovided above the semiconductor layer and comprising a first opening ina region which overlaps the semiconductor layer; an organic insulatingfilm provided above the semiconductor layer and comprising a secondopening in a region which overlaps the first opening; a metal filmstacked on the semiconductor layer on an inner side of the region wherethe second opening is formed; and a pixel electrode provided in thefirst opening and the second opening to be in contact with the metalfilm and the semiconductor layer, the metal film being spaced from afirst side surface of the first opening and a second side surface of thesecond opening.
 2. The display device of claim 1, further comprising: asecond inorganic insulating film provided between the semiconductorlayer and the organic insulating film, wherein the organic insulatingfilm is provided between the semiconductor layer and the first inorganicinsulating film, and the second inorganic insulating film comprises athird opening in a region which overlaps the first opening and thesecond opening.
 3. The display device of claim 2, wherein the metallicfilm is spaced from a third side surface of the third opening.
 4. Thedisplay device of claim 3, wherein the pixel electrode is in contactwith the semiconductor layer between the third side surface and themetal film.
 5. The display device of claim 2, wherein the firstinorganic insulating film covers the second side surface and is incontact with the second inorganic insulating film in the second opening.6. The display device of claim 1, wherein the first inorganic insulatingfilm is provided between the semiconductor layer and the organicinsulating film, and the pixel electrode covers the second side surfaceand is in contact with the first inorganic insulating film in the secondopening.
 7. The display device of claim 6, wherein the pixel electrodecovers the first side surface and is in contact with the semiconductorlayer between the first side surface and the metal film.
 8. The displaydevice of claim 1, wherein at least one end portion of the metal film isin contact with a fourth side surface of the first opening.
 9. Thedisplay device of claim 2, further comprising: a first wiring portionand a second wiring portion disposed on the second inorganic insulatingfilm and covered by the organic insulating film, wherein the firstopening, the second opening and the third opening are located betweenthe first wiring portion and the second wiring portion in plan view. 10.The display device of claim 6, further comprising: a first wiringportion and a second wiring portion disposed on the first inorganicinsulating film and covered by the organic insulating film, wherein thefirst opening and the second opening are located between the firstwiring portion and the second wiring portion in plan view.
 11. Thedisplay devices of claim 9, wherein the first wiring portion and thesecond wiring portion are formed from a same material as that of themetal film.
 12. The display device of claim 9, wherein a width of themetal film is equal to or less than that of the first wiring portion andthe second wiring portion.
 13. The display device of claim 1, furthercomprising: a second substrate opposing the first substrate; and aliquid crystal layer between the first substrate and the secondsubstrate.
 14. A wiring substrate comprising: a semiconductor layer; afirst inorganic insulating film provided above the semiconductor layerand comprising a first opening in a region which overlaps thesemiconductor layer; an organic insulating film provided above thesemiconductor layer and comprising a second opening in a region whichoverlaps the first opening; a first conductive layer stacked on thesemiconductor layer on an inner side of the region where the secondopening is formed; and a second conductive layer formed in the firstopening and the second opening to be in contact with the firstconductive layer and the semiconductor layer, the first conductive layerbeing spaced from a first side surface of the first opening and a secondside surface of the second opening, and the second conductive layerbeing in contact with the semiconductor layer between the first sidesurface and the first conductive layer.
 15. The wiring substrate ofclaim 14, wherein at least one end portion of the first conductive layeris in contact with a fourth side surface of the first opening.
 16. Adisplay device comprising: a source line, a semiconductor layerelectrically connected to the source line, a relay electrodeelectrically connected to the semiconductor layer and a pixel electrodeconnected to the relay electrode, a width of the relay electrode is lessthan a width of the source line.
 17. The display device of claim 16,further comprising: a second insulating film which covers thesemiconductor layer, a gate line formed above the second insulatingfilm, a third insulating film which covers the gate line, a fourthinsulating film formed above the third insulating film and covering thesource line, wherein the pixel electrode is formed above the fourthinsulating film, and the relay electrode and the pixel electrode are incontact with the semiconductor layer in a contact hole formed in thesecond insulating film and the third insulating film.